Automatic speed control for motor cars



Aug. 16, 1927.

L. w. DAVIS ET AL AUTOMATIC SPEED CQNTROL FOR moron CARS Filed Sept. 22, 1924 Patented Aug. 16, 1927.

UNITEDLSTATES PA 1,638,836 TENT OFFICE.

LESLIE W. DAVIS AND EDMUND S. BURSLEY, 0F DEXTER, MAINE.

AUTOMATIC SPEED CONTROL FOR MOTOR CARS.

Applicationfiled September 2 2, 1924. Serial No. 739,001.

The present invention deals with the problem of automatically controlling or limiting the speed of motor cars at any predetermined point'by preventing the motor from functioning when the speedometer reaches a certain position indicative of a predetermined rate of speed. p

In general terms, the invention consists in the combination with a speedometer, of an ignition circuit for the motor, of means operative at a predetermined speed-indicating position of the speedometer for breaking the ignition circuit to prevent ignition of the explosive mixture of air and gas which drives the car. Provision is also 7 made for setting the ignition cut-out device controlled by the speedometer at different positions of adjustment so that the interruption of the ignition circuit may be caused at difierent speeds, according to regulations or desire of the driver.

These and other features of the invention will be particularly described in the following specification and will be defined in the claim hereto annexed.

In the accompanying drawings we have illustrated a simple construction and arrangement easily applicable to different types of motor cars as illustrating the prin ciples of this invention, in which:

Figure 1 is a side elevation partly broken away to show the arrangement of speedometer and its associated circuit breaking device.

Figure 2 is a plan View of the same partly in section'to show the working parts by which the interruption of the circuit is effected by the speedometer.

Figure 3 is a diagrammatic view illustrating the ignition circuit and the'controlling circuit by which the former is interrupted through the agency of the Speedometer. Y i

The principles of this invention are ap plicable to any known form of speed-indicating device which moves to different positions in correspondence with the rate of speed of the vehicle which carries it'. For purposes ofillustration we have shown a common type of speedometer embracing a casing 1, and an oscillatory member2 working against a balance spring 2 provided with suitable transmission means operated from one of the vehicle wheels or other suitable element of the car whose rate of movemerit corresponds to the speed of the car.

circuit.

On the oscillatory member or disk 2, is placed a pin or projection 3, which moves through'an arc of the circle to indicate dif ferent car speeds.

On the side of the speedometer casing 1, is mounted a bracket 4 on which is supported a pivotal arm or lever 14 normally held by a very light tension spring 14"-, against a fixed stop pin 14". The inner end of this lever projects into the path of the projecting pin 3, carried by the disk 2.

This arm or lever 14 forms one contact member of a shunt circuit a and is opposed by another yielding contact member or arm 8, as illustrated in Figures 2 and 3. This shunt circuit a includes an electro-magnet coil 8 and is normally open or inactive. 7

When the pin 3 of the movable element of the speedometer travels far enough to exert a slight thrustor push on the arm 14 the latter swings on its pivot until its outer end touches the yielding contact 8, and thus the electric circuit, through the magnet coil, is closed thereby energizing the magnet to in terrupt or break the ignition circuit 6 which leads to the distributor 0, whence proceed the separate branch circuits to the respective spark plugs d, cl, d andd Any suitable type of make and break device or circuit-breaker may be associated with the electro-magnet. In this case we have shown a pivoted bell-crank arm 9, normally held by a light tension spring with its adjustable contact 10 abutting againstjan opposing contact member 11 forming part of the ignition Opposite the core of the magnet this arm is provided with a piece of soft iron, as shown at 13, so that the energizing of the magnet draws this end of the bellcrank arm against the magnet core, thus breaking the contact between the terminals 10 and 11.

,To make convenient provision for setting the device so that the breaking of the ignition circuit may take place at any desired speed-indicating position of the speedometer, the bracket 4, carrying the magnetcontrolling arm 14, is made adjustable in the direction of movement of the speedometer disk 2. To this end thecasing 1 is provided with a circumferential slot extending through a substantial arc, and through this slot are passed the fastening screws which are tapped into the bracket 4 so as to hold it in any desired position of circumferential adjustment. The slot may be closed by means of an arouate cover strip provided with holes for the passage of the fastening screws, but having sufiicient length to overlap the entire slot in all positions of adjustment of the bracket 4.

While for the purposes of illustration the speedometer shown is of the type having a circular movement, ,it will, of course, be understood that precisely the same principles are applicable to any type of speedometer having a movable element controlled according to the speed of the car.

In normal operation the current from the battery passes through the circuit 1) to the distributor 0 and in predetermined order to the respective spark plugs of themotor cylinders, ,in the usual and well known manner. The closing of the shunt circuit a, through the above-described action of the speedometer, instantly breaks the ignition circuit and keeps it open as long as the speedometer presses against the magnetenergizing arm 1%. As the speed of the car decreases and the speedometer moves away from contact with the arm let, the latter returns to normal position, thereby opening the shunt circuit and releasing the circuitbreaker in the ignition circuit from its open to .its closed position.

WVhat we claim is:

In an automatic'spee'd control for motor cars, the combination with a rotatable speedindicating member and its surrounding casing, of a circumferentially adjustable bracket secured to said casing, circuit containing a normally closed switch, a shunt circuit including an electronnagnet arranged, when energized, to open said switch, a spring-actuated lever pivotally mounted on said adjustable bracket and adjustable therewith circ'umterentially of'the speed-indicating member, said leverbeing also arranged to be engaged in its difi ere'nt positions ot' adj'ustn'ient by said indicating inemberand forming a normally open con tact member movable to circuit-closing position by engagement with said speed-indieating member at predeterminedspeed indir eating positions thereof, substantially as described.

In witnes'swhereof, we have subscribed the above specification.

LESLIE WV. DAVIS. EDMUND" S. B'URSLEY.

a motor ignition 

